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Sports Physiology Prof. dr. Zoran Valić Department of Physiology University of Split School of Medicine.

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Presentation on theme: "Sports Physiology Prof. dr. Zoran Valić Department of Physiology University of Split School of Medicine."— Presentation transcript:

1 Sports Physiology Prof. dr. Zoran Valić Department of Physiology University of Split School of Medicine

2 heavy exercise is extreme stresses for body heavy exercise is extreme stresses for body high fever 100% in metabolism high fever 100% in metabolism marathon race 2000% in metabolism marathon race 2000% in metabolism

3 Female and Male Athletes: muscle strength, pulmonary ventilation and CO 2/3-3/4 of values recorded in men muscle strength, pulmonary ventilation and CO 2/3-3/4 of values recorded in men strength per cm 2 equal (30-40 N/cm 2 ) strength per cm 2 equal (30-40 N/cm 2 ) marathon race 11% slower marathon race 11% slower two-way swim across English Channel two-way swim across English Channel Testosterone (40% more muscle mass) Testosterone (40% more muscle mass) 27% & 15% percent body fat, respectively 27% & 15% percent body fat, respectively aggressiveness aggressiveness

4 Strength, Power, and Endurance of Muscles 1) What the muscles can do for you? 2) What strength they can give? 3) What power they can achieve? 4) How long they can continue their activity?

5 Muscle force (strength): determined mainly by muscle size (training) determined mainly by muscle size (training) maximal contractile force – N/cm 2 maximal contractile force – N/cm 2 quadriceps is 150 cm 2 (F= N) quadriceps is 150 cm 2 (F= N) rupture & avulsion of tendons, displaced cartilages, compression fractures and torn ligaments rupture & avulsion of tendons, displaced cartilages, compression fractures and torn ligaments

6 Holding strength (force) of muscles: force that attempts to stretch out already contracted muscle force that attempts to stretch out already contracted muscle greater about 40% than contractile strength greater about 40% than contractile strength F quadriceps = N F quadriceps = N internal tearing in the muscle internal tearing in the muscle

7 Power of Muscular Contraction: mechanical work (W) performed by muscle is amount of force applied by the muscle multiplied by the distance over which the force is applied mechanical work (W) performed by muscle is amount of force applied by the muscle multiplied by the distance over which the force is applied power (P) is total amount of work that muscle performs in a unit period of time (t) power (P) is total amount of work that muscle performs in a unit period of time (t)

8 determined not only by the strength but also: distance of contraction and the number of times that it contracts each minute determined not only by the strength but also: distance of contraction and the number of times that it contracts each minute power is generally measured in watts (W, or in kilogram meters (kg-m) per minute) power is generally measured in watts (W, or in kilogram meters (kg-m) per minute)

9 Maximal power of all muscles: Duration of contraction P (W, kg-m/min) first 8 to 10 seconds next 1 minute next 30 minutes 1200/ / /1700

10 Athletic (muscle) efficiency: power efficiency power efficiency velocity of 100-meter dash is only 1.75 times as great as velocity of a 30-minute race velocity of 100-meter dash is only 1.75 times as great as velocity of a 30-minute race depends on muscle supply by nutrients (glycogen) depends on muscle supply by nutrients (glycogen)

11 (measured by time): Endurance (measured by time): Nutrition Time (min) high-carbohydrate diet mixed diet high-fat diet

12 Amounts of glycogen stored in the muscle: Nutrition high-carbohydrate diet Amount of glycogen (g/kg muscle) high-carbohydrate diet mixed diet high-fat diet 40206

13 Muscle Metabolic Systems in Exercise: 1) phosphocreatine-creatine system 2) glycogen-lactic acid system 3) aerobic system

14 Phosphagen system: ATP (adenosine – PO 3 PO 3 PO 3 - ) ATP (adenosine – PO 3 PO 3 PO 3 - ) high-energy P bonds (7.3 Cal/mol ATP) high-energy P bonds (7.3 Cal/mol ATP) amount of ATP sufficient for only about 3 s amount of ATP sufficient for only about 3 s phosphocreatine (creatine phosphate, creatine PO 3 - ) phosphocreatine (creatine phosphate, creatine PO 3 - ) 10.3 Cal/mol creatine, quick transfer 10.3 Cal/mol creatine, quick transfer 2-4 x more phosphocreatine than ATP 2-4 x more phosphocreatine than ATP combined 8-10 s of maximal muscle power combined 8-10 s of maximal muscle power

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16 Glycogen-Lactic Acid System: glycogen glucose (glycolysis, anaerobic metabolism) glycogen glucose (glycolysis, anaerobic metabolism) two pyruvic acid molecules – 4 ATP two pyruvic acid molecules – 4 ATP without oxygen – lactic acid without oxygen – lactic acid 2.5 x more rapid than oxidative mechanism 2.5 x more rapid than oxidative mechanism provides additional 1.3 to 1.6 minutes of maximal muscle activity ( m) provides additional 1.3 to 1.6 minutes of maximal muscle activity ( m)

17 Aerobic System: glucose, fatty acids, and amino acids glucose, fatty acids, and amino acids

18 ATP generation per minute: Mechanism of Energy Supply M ATP/min phosphagen system glycogen-lactic acid system aerobic system

19 System endurance: Mechanism of Energy Supply Time phosphagen system glycogen-lactic acid system aerobic system 8-10 s min unlimited

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21 Reconstitution of the lactic acid system: removal of the excess lactic acid (extreme fatigue): removal of the excess lactic acid (extreme fatigue): 1) small portion is converted back into pyruvic acid 2) remaining lactic acid is reconverted into glucose (in the liver)

22 Recovery of the Aerobic System After Exercise: 1) Oxygen Debt 2) Recovery of Muscle Glycogen

23 Oxygen debt: body contains about 2 L of stored oxygen: body contains about 2 L of stored oxygen: 1) 0.5 L in the air of the lungs 2) 0.25 L dissolved in the body fluids 3) 1L combined with the hemoglobin 4) 0.3 L stored in muscle fibers (myoglobin) all this stored oxygen is used within minute all this stored oxygen is used within minute 9 L more reconstituting both phosphagen system and lactic acid system 9 L more reconstituting both phosphagen system and lactic acid system total 11.5 L O 2 – oxygen debt total 11.5 L O 2 – oxygen debt

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25 Recovery of Muscle Glycogen: complex matter, often requires days complex matter, often requires days

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27 it is important for an athlete to have a high- carbohydrate diet before a grueling athletic event it is important for an athlete to have a high- carbohydrate diet before a grueling athletic event not to participate in exhaustive exercise during the 48 hours preceding the event not to participate in exhaustive exercise during the 48 hours preceding the event

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29 Effect of Athletic Training: muscle strength is not increased without load muscle strength is not increased without load 6 nearly maximal contractions performed in three sets 3 days a week – approximately optimal increase in muscle strength, without producing chronic muscle fatigue 6 nearly maximal contractions performed in three sets 3 days a week – approximately optimal increase in muscle strength, without producing chronic muscle fatigue 30% in strength during 6-8 weeks 30% in strength during 6-8 weeks simultaneously equal increase in muscle mass – muscle hypertrophy simultaneously equal increase in muscle mass – muscle hypertrophy

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31 Muscle Hypertrophy: heredity & testosterone secretion heredity & testosterone secretion % increase with training % increase with training 1) increased diameter of the muscle fibers 2) increased numbers of fibers?

32 Changes that Occur Inside the Hypertrophied Muscle Fibers: 1) numbers of myofibrils 2) mitochondrial enzymes for 120% 3) ATP and phosphocreatine for 60-80% 4) stored glycogen for 50% 5) stored triglyceride (fat) for %

33 Muscle Fibers Types: 1) fast-twitch muscle fibers – (gastrocnemius) – type II (white, a & b) 2) slow-twitch muscle fibers – (soleus) – type I (red)

34 Basic differences between: 1) diameter of fast-twitch fibers 2x larger 2) enzymes for anaerobic metabolism 2-3x more active in fast-twitch fibers (power) 3) slow-twitch fibers are organized for endurance, generation of aerobic energy (more mitochondria and myoglobin) 4) slow-twitch fibers – more capillaries genetic inheritance genetic inheritance

35 % of fiber types in quadriceps: ActivityFast-twichSlow-twich MarathonersSwimmers Average male Weight lifters SprintersJumpers

36 Respiration in Exercise: depends on sport discipline, duration of activity depends on sport discipline, duration of activity

37 Oxygen Consumption Under Maximal Conditions: Type of subject VO 2MAX (mL/min) Untrained average male Trained average male Male marathon runner oxygen consumption for young man at rest is about 250 ml/min

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39 Pulmonary Ventilation (PV): Condition PV (L/min) Pulmonary ventilation at maximal exercise Maximal breathing capacity

40 Limits of Pulmonary Ventilation: MBC 50% higher than PV during maximal exercise MBC 50% higher than PV during maximal exercise respiratory system is not normally the most limiting factor in delivery of oxygen respiratory system is not normally the most limiting factor in delivery of oxygen element of safety if: element of safety if: 1) exercise at high altitudes 2) exercise under very hot conditions 3) abnormalities in respiratory system

41 Effect of Training on Vo 2 Max: Vo 2 Max – rate of oxygen usage under maximal aerobic metabolism Vo 2 Max – rate of oxygen usage under maximal aerobic metabolism Vo 2 Max of a marathoner is about 45 percent greater than that of an untrained person (genetically determined, many years of training) Vo 2 Max of a marathoner is about 45 percent greater than that of an untrained person (genetically determined, many years of training)

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43 Oxygen-Diffusing Capacity of Athletes: Condition DC (ml/min) Nonathlete at rest Nonathlete during ME Speed skaters during ME Swimmers during ME Oarsman during ME ME – maximal exercise

44 3x increase in DC (activation of the pulmonary capillaries) 3x increase in DC (activation of the pulmonary capillaries) training procedures increases DC training procedures increases DC partial pressures (O 2 & CO 2 ) remain nearly normal during strenuous athletics partial pressures (O 2 & CO 2 ) remain nearly normal during strenuous athletics regulation of breathing regulation of breathing negative effects of smoking (acute and chronic) negative effects of smoking (acute and chronic)

45 Cardiovascular System in Exercise: delivering required oxygen and other nutrients to the exercising muscles delivering required oxygen and other nutrients to the exercising muscles arterial blood pressure regulation arterial blood pressure regulation flow decrease during each muscle contraction flow decrease during each muscle contraction blood flow to muscles during exercise increases markedly (up to 25x) blood flow to muscles during exercise increases markedly (up to 25x)

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47 Maksimalno povećanje protoka: Condition Blood Flow (ml/min/100g) Resting blood flow Blood flow during maximal exercise

48 Mechanisms of Blood Flow Increase: 1) vasodilation caused by the direct effects of increased muscle metabolism 2) moderate increase in arterial blood pressure (30%) 3) muscle pump 4) FMD 5) other theories

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50 CO During Exercise: Condition CO (L/min) CO in young man at rest Maximal CO during exercise in young untrained man Maximal CO during exercise in average male marathoner (35-40)

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53 Relation of Cardiovascular Performance to Vo 2 Max: SV & HR increase to 95% of maximal SV & HR increase to 95% of maximal CO is 90% of maximal CO CO is 90% of maximal CO PV is 65% of maximal breathing capacity PV is 65% of maximal breathing capacity CO decreases for 50% between age of 20 and 80, maximal breathing capacity decreases even more, there is a reduction in skeletal muscle mass as well CO decreases for 50% between age of 20 and 80, maximal breathing capacity decreases even more, there is a reduction in skeletal muscle mass as well

54 Body Heat in Exercise: maximal efficiency 20-25% maximal efficiency 20-25% energy converted in muscle work is ultimately transferred into heat energy converted in muscle work is ultimately transferred into heat 1) friction within muscles and joints 2) friction due to blood flow

55 Heatstroke: with very hot and humid conditions or excess clothing body temperature can easily rise to 106°-108°F (41°-42°C) with very hot and humid conditions or excess clothing body temperature can easily rise to 106°-108°F (41°-42°C) extreme weakness, exhaustion, headache, dizziness, nausea, profuse sweating, confusion, staggering gait, collapse, unconsciousness death extreme weakness, exhaustion, headache, dizziness, nausea, profuse sweating, confusion, staggering gait, collapse, unconsciousness death temperature-regulating mechanism fails temperature-regulating mechanism fails positive feedback-loop positive feedback-loop

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57 Body Fluids and Salt in Exercise: 5-10 pound weight loss has been recorded in athletes in a period of 1 h during endurance athletic events in hot and humid conditions 5-10 pound weight loss has been recorded in athletes in a period of 1 h during endurance athletic events in hot and humid conditions loss of sweat, significantly performance loss of sweat, significantly performance weight loss 5-10% – muscle cramps, nausea weight loss 5-10% – muscle cramps, nausea acclimatization, salt lost, aldosterone (increasing reabsorption of from sweat) acclimatization, salt lost, aldosterone (increasing reabsorption of from sweat) supplement of K + supplement of K +

58 Drugs and Athletes: caffeine (three cups of coffee 7% improve) caffeine (three cups of coffee 7% improve) androgens or anabolic steroids (risk of cardiovascular damage) androgens or anabolic steroids (risk of cardiovascular damage) amphetamines and cocaine (?, deterioration of performance, sudden death due to ventricular fibrillation) amphetamines and cocaine (?, deterioration of performance, sudden death due to ventricular fibrillation)

59 Body Fitness Prolongs Life: people who maintain appropriate body fitness have the additional benefit of prolonged life people who maintain appropriate body fitness have the additional benefit of prolonged life mortality is 3x less in the most fit people than in the least fit mortality is 3x less in the most fit people than in the least fit

60 Mechanisms: 1) greatly reduce cardiovascular disease (MI & stroke) a) maintenance of lower blood pressure b) reduced blood cholesterol and LDA, and increase in HDL 2) fit person has more bodily reserves to call on when does become sick (pneumonia, cardiac reserve)


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